Background: Irritable Bowel Syndrome (IBS) is a chronic functional gastrointestinal (GI) disorder characterized by abdominal pain, altered bowel habits, and bloating, affecting approximately 10.1% of the global population. While current treatments emphasize dietary modifications and symptom management, emerging evidence suggests that physical activity (PA) may help alleviate IBS symptoms. This study evaluated the effects of a structured walking program, “StepFit-18K”, on IBS symptom relief. Methods: A total of 106 participants (68 females and 38 males) completed the 12-week intervention, which consisted of 18,000 additional steps per week (6000 extra steps on three days per week) tracked via fitness devices. The program emphasized step count, ease of adoption, and social support through walking groups. Results: As assessed by validated questionnaires, significant reductions in GI symptoms were observed. The IBS Symptom Severity Score (IBS-SSS) decreased from 118.30 ± 98.73 to 74.46 ± 74.93, with a delta score of −43.84%, highlighting bloating as the most improved symptom. No clinically significant changes were observed in anthropometric or biochemical markers. Conclusions: StepFit-18K is a simple, accessible, and effective form of physical activity that has demonstrated therapeutic benefits for IBS symptoms. This offers an additional application beyond its well-established role in preventing cardiovascular diseases.